Chronic Pain in the Elderly Complicates Depression Therapy

NEW ORLEANS—Elderly patients with chronic pain are less likely to respond to collaborative care treatment of depression, investigators reported at the American Association of Geriatric Psychiatry annual meeting.

Chronic pain affects 70% to 80% of older adults, mostly related to osteo-arthritis. Depression is associated with an increased incidence of persistent pain. Patients with both conditions have greater impairment, as well as greater healthcare use and expenditures than pain-free patients with depression, noted Stephen M. Thielke, MD, lead investigator of Improving Mood: Promoting Access to Collaborative Treatment (IMPACT), who is at the Division of Geriatric Mental Health, University of Washington, Seattle.

Dr Thielke’s study was a secondary analysis of IMPACT, the largest treatment trial to date on late-life depression. IMPACT included 1801 older adults with depression from 18 primary care clinics across the United States and lasted 2 years, comparing a collaborative intervention with usual care for depression.

Baseline pain was common in the entire study population, reported by nearly 1000 patients. The study compared groups reporting no/low baseline pain and high pain, as assessed by pain interference (the degree to which pain interferes with normal activities), arthritis pain intensity, and arthritis interference. Treatment response was defined as a >50% reduction in Hopkins Symptom Checklist Score at 12 months.

The collaborative intervention was overseen by a depression care manager, usually a nurse, in consultation with psychiatrists and primary care physicians. About half of the patients received antidepressants; the other half received interpersonal psychotherapy.

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At 12 months, the presence of baseline pain was significantly associated with a worse response to treatment for depression in the intervention group. Responses were seen in 48.9% of patients with no/low pain interference compared with 37.4% in those with high pain interference ( = .001).

Patients with high levels of pain interference were almost 40% less likely to respond to the intervention. “We were very interested in why some patients did not respond to treatment, and the only thing that emerged as an independent predictor was pain,” Dr Thielke said. “We believe that when you are in pain, you learn that the best thing to do is nothing. While this is good for managing pain, inactivity is not a good treatment for depression.”

Pain was not particularly correlated with depression at baseline, “so it was not that patients who were hurting were more depressed,” he added. The analysis also showed that the most severely depressed patients responded best to the intervention.

Duloxetine Effective for Refractory Depression

In a separate study, the selective serotonin and norepinephrine reuptake inhibitor (SSNRI) duloxetine (Cymbalta) proved effective for depression in older adults who did not respond to a selective serotonin reuptake inhibitor (SSRI). Duloxetine is marketed as targeting the emotional and physical symptoms of depression.

The study included 216 patients aged ≥60 years. Of these, 40 patients were partial or nonresponders to an SSRI and were subsequently switched to the SSNRI duloxetine, at an average dose of 95 mg/day.

After a median treatment duration of 22 weeks, 52.5% of the refractory patients responded to the SSNRI, a finding that lead investigator Jordan F. Karp, MD, of the University of Pittsburgh, referred to as “really remarkable.” He noted that this was an independent study that was not funded by the manufacturer of duloxetine (Eli Lilly).

Even at this high dose (95 mg/d), the drug was well tolerated, he said, adding that he had pushed the dose to 120 mg/day without problems in very difficult cases.

Jules Rosen, MD, chief of the Geriatric Psychiatry Services at the University of Pittsburgh, commented on both studies. “When I see just run-of-the-mill depression in a nursing home resident, I know sooner or later I will get them to respond. But if they have chronic pain, there will be an additional challenge,” he said. “I will give more aggressive medical therapy, add psychotherapy, or go to duloxetine.”

He said physicians can help their patients “identify their pain in the here and now.” He has “learned that chronic pain patients can have anticipatory pain; that is, they feel pain when they just think about getting out of bed….In such patients I have taken them off narcotics, and used psychotherapy and duloxetine, and they did beautifully.”